TV veteran Marta Kauffman also revealed why the show has a younger fanbase than you'd expect.

[Editor’s note: Spoilers follow for the season finale of “Grace and Frankie” Season 4.]

“Grace and Frankie” co-creator Marta Kauffman has been telling stories about life over 70 for four seasons now, but there’s no sign of the show running out of tales to tell, as evidenced by the announcement Wednesday of Netflix renewing the show for a fifth season.

“Every season, it becomes more and more special, because you know you have fewer and fewer left,” she said to IndieWire at SCAD aTVfest in Atlanta. But that doesn’t mean there’s anything resembling a game plan for ending the show. Instead, Kauffman said that if Netflix gave her the option to keep the show going for as long as she wanted, “I’d probably tell them, ‘Let’s do it as long as it’s still comfortable for Jane and Lily.'”

It’s a fair consideration, given the current ages of stars Jane Fonda and Lily Tomlin (80 and 78, respectively). But “they’re doing well,” Kauffman said. “It could be years and years. Who knows?”

Kauffman (who created “Grace and Frankie” alongside Howard J. Morris) said that the writers have been at work already on stories for Season 5, which will pick up on the show-changing events of the Season 4 finale.

“The way it is with every season, the hope is that you’ve left enough good bird seed that you can find your way. That’s the hope is you’ve dropped all these clues that we can as writers take advantage of in the next season,” she said. “You want stories to continue and not just to stop.”

That said, in writing Season 4, Kauffman said, “We were focused on Season 4 until we got to the last episode — and then said, what do we want to set up for Season 5?”

The big twists of that final episode, which included Grace and Frankie getting convinced by their children to move into an “assisted living” facility and the surprise sale of Grace and Frankie’s beloved beach house, created no shortage of storylines for a new season. Also, according to Kauffman, “People were mad. People were mad at the kids because they sold the house.”

That anger is understandable, but for people of a certain age it’s also quite relatable — even within the “Grace and Frankie” writers’ room. “So many of my writers are going through this with their own parents,” Kauffman said. “We’ve got quite a mixture in the room; there are several writers going through the exact thing right now where their parents are… They’re worried. They’re worried and they want to keep them safe.”

Four older people who are definitely safe, as far as Kauffman is concerned, are the characters of Grace, Frankie, Sol (Sam Waterston), and Robert (Martin Sheen). While the four leads are all of an age where, in the real world, anything could happen health-wise, Kauffman didn’t think that the writers would ever actively choose to lose a character.

“It doesn’t mean it couldn’t happen. We gave Robert a heart attack already — health issues are definitely real issues. But, no, it would be so mean to kill one of them off just for the sake of killing one of them off,” she said. “When you love characters as we love characters… how would I pick who’d I’d give some horrible death to? I can’t even imagine.”

There is, of course, the reality that something could happen to one of the actors, but as Kauffman fairly noted, “This could happen on any show, not just mine. Then we would deal with it. But it’s not a plan.”

And it’s not really a narrative the show needs at this point. “There’s plenty of other stuff about aging,” she said.

Kauffman acknowledged that in “Grace and Frankie’s” early days, figuring out the tone of the show wasn’t an instantaneous process, especially when it came to balancing the dramatic and comedic elements of its premise. In the first season, she said, Netflix “kept tugging us to lean into the drama and we sort of had to find the line between the two.”

In addition, it took some time to learn key things about what works best for the series. “We learned that our show doesn’t do broad well,” was just one example. “We can’t do broad.”

But after four seasons, the show’s definitely found its voice — not to mention an audience that defies expectations. “It is fascinating, we have a much younger audience than we thought we’d ever get. Jessica Biel just posted herself nursing her baby and watching ‘Grace and Frankie.’ Miley Cyrus likes the show,” she said. “My understanding is… at least what I’m hearing is that there are two things to it. One is that I believe in the universal story as a universal story, no matter what the age is. But I think a number of young women feel that the show makes aging less frightening.”

Looking forward at Season 5, Kauffman foresaw opportunities for both new love interests and returning ones, including Nick (Peter Gallagher), Grace’s former boyfriend as of the end of Season 4. “Nick comes back in a substantial way,” she said.

Kauffman didn’t mention any other casting plans, though in a subsequent announcement Netflix revealed that RuPaul will appear as “‘Benjamin Le Day,’ a formidable and quick-witted adversary who faces off with Grace and Frankie.”

However, when asked about anyone else she might dream of casting, she noted that “to a certain extent, I have my dream cast. I have Jane, Lily, Martin and Sam and the four kids.”

And in general, they don’t write with a specific actor in mind. “For each new character that is created for the show, you have a dream cast. Whether or not you can get them is a whole other story. But for the most part we don’t go into it saying, ‘God, I wish we could get Shirley MacLaine’ more than, ‘Oh, here’s a part, oh my God, Shirley MacLaine would be so perfect for it.'”

Added Kauffman, “Not that I wouldn’t give my right arm to work with Shirley MacLaine.”

The one hurdle Kauffman mentioned encountering in the casting process was that “we’re reaching for people who don’t really want to do television” — which is still apparently a thing in the era of Peak TV.

“A lot of people do [want to do it] but there are a lot of people who don’t, who still have a certain judgment about it,” she said.

It’s an attitude that Kauffman, as a writer of television, doesn’t share. “I feel as far as TV goes, TV is a very intimate experience between the show and the audience. TV comes into your home, it comes with your computer when you’re in bed. You’re watching it when you’re naked and when you’re folding laundry and when you’re making dinner or when you’re in your robe and it’s really intimate because you’ve invited all these people into your home. In your most intimate state. So I feel like it’s an incredibly close relationship you have with the audience,” she said.

“There is a magic to the whole thing that you can’t teach, you can’t explain,” she continued. “Sometimes, the stars are just aligned.”

“Grace and Frankie” Season 4 is streaming now on Netflix. Season 5 will return in 2019.